Natural ventilation systems are intended to provide sufficient outside air to achieve appropriate standards of air quality and to provide cooling when needed. Since the cooling capacity of natural ventilation is limited, a key design challenge is to limit heat gains through good solar control and careful management of the internal gains. Naturally ventilated buildings do not aim to achieve constant environmental conditions, but take advantage of dynamics to provide comfortable, controllable conditions for the occupants

Natural ventilation systems need to be designed to achieve two key aspects of environmental performance:

• Ventilation to maintain adequate levels of indoor air quality
• In combination with other measures, ventilation can reduce the tendency for buildings to overheat, particularly in summer